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As early as the 1950s researchers were
struck by the lower rates of heart disease, stroke and some kinds of
cancer they observed among people who consumed what has come to be known
as “the Mediterranean diet.” A 30-year, 7-nation comparative study
sponsored by the World Health Organization spurred even further interest
when it confirmed unusually low rates of heart disease among men from
the Isle of Crete, even though they consumed surprisingly high levels of
fat.
Through these early research findings, a
picture developed of this Mediterranean diet—one built on bread, fruit,
vegetables, fish, a few dairy foods, and two surprise ingredients—wine
and olive oil. And an enormous amount of research has been devoted to
identifying its benefits and explaining how it works.
In an August 2009 article on “Effects of
the Mediterranean diet on longevity and age-related morbid conditions,”
a team led by Dr. Faustino Perez-Lopez of the University of Zaragoza and
the Hospital Clínico de Zaragoza in Spain offered a comprehensive
overview of this research on how the Mediterranean diet effects
longevity, metabolic syndrome (METS), hypertension, cardiovascular
disease, obesity, cancer and various other health conditions. They also
look at the details of the Mediterranean diet within the larger context
of Mediterranean culture and life to help us understand both its power
and some of its possible limitations.
Living Longer
Following the groundbreaking WHO survey,
subsequent research from all around the world has been remarkably
consistent in confirming an association between following a
Mediterranean diet and increased life expectancy, especially for the
elderly.
Older European men and women who followed
the Mediterranean diet (MD) had a significantly lower annual risk of
dying—as much as 23% [2]. U.S. research sponsored by the National
Institutes of Health and the AARP reported a 20% lower mortality rate
over a ten-year period among older people whose diets closely matched
the MD profile [3]. And in Australia researchers traced a comparable
link between a Mediterranean-type diet and reduced cardiovascular
disease and mortality.
Another major project, the European
Prospective Investigation into Cancer and Nutrition (EPIC) Elderly
study, found that a healthy 60-year-old man whose diet fits the MD
profile was likely to live at least one year longer than a man of the
same age on a different diet.
These are compelling numbers for a
rapidly aging demographic worldwide.
Mediterranean Diet and the Metabolic
Syndrome
The “metabolic
syndrome” (METS) is
a group of factors linked to excess weight that increase the risk of
heart disease, diabetes, stroke and other health problems. The primary
signs are excess abdominal fat, high triglyceride levels, low HDL
cholesterol, high blood pressure, and elevated fasting blood glucose
levels. Metabolic syndrome is diagnosed when at least three of these
heart disease risk factors are present. Sufferers have twice the chance
of heart disease and five times that of diabetes. It may affect as much
as a quarter of the general population and is more common among older
people.
Several studies have found that the
metabolic syndrome is less common among people whose diet mirrors the
Mediterranean diet. The ATTICA Study in Greece looked at some of the
specific dietary components and found that people who consumed more meat
and alcohol showed more of the metabolic syndrome risk factors, while
those who ate more fruits and vegetables, fish, grains and legumes (all
features of the MD), had fewer symptoms.
Treatment studies comparing a couple of
MD-type diets with low-fat diets found that the healthy fats that form
part of a normal Mediterranean diet—i.e., olive oil and nuts—may
actually be more effective at reducing cellular fat and harmful LDL than
a low-fat diet [5]. Other studies have linked a reduced incidence of
diabetes with the consumption of vegetable fats like olive oil (instead
of transfatty acids) and moderate amounts of alcohol in the
Mediterranean diet.
Blood Pressure, Heart Disease, and
Obesity
Eating more fruits and vegetables and
less fat and cholesterol are standard recommendations for reducing
hypertension and losing weight. Portions of the EPIC Study focused on
Greece and Italy both established that a Mediterranean diet involving
the consumption of olive oil and vegetables had a positive effect on
blood pressure levels. In other research, the combination of olive oil
and wine was found to cause an immediate decrease in blood pressure
after a meal.
Even among people genetically predisposed
to cardiovascular disease, the Mediterranean diet combined with olive
oil or nuts has been found to reduce several risk factors, including
blood sugar levels, cholesterol/HDL-C ratios, and blood pressure—again,
even more effectively than a low-fat diet. A Mediterranean diet equaled
the success of low-fat diets in lowering the mortality rates for people
who had suffered heart attacks.
The key to many of these benefits seems
to lie in the protective and preventive properties of plant-derived
chemicals found in nuts, virgin olive oils, whole grains, vegetables,
beans, fruits, and herbs. Studies are increasingly exploring the
mechanisms behind these phytochemicals.
Obesity is one of the primary
contributors to both diabetes and cardiovascular disease. At a time when
obesity and overweight are beyond epidemic levels, affecting 30 to 50%
of the population, it is highly significant that following a
Mediterranean diet has been found strongly associated with lower body
mass indices and a lower propensity for weight gain in Greek, Spanish
and Italian subjects included in the EPIC and other studies.
Cancer and other health issues
Many of the components of a typical
Mediterranean diet are linked to lower cancer risks as well.
The tomatoes, fish and fish oils, and
unrefined olive oils all contain potential anticarcinogens. Olive oil,
whole grains and fruits and vegetables may treat or reduce the risk of
malignant tumors in many locations. And again, any reduction of
overweight and obesity has repercussions on obesity-related cancers,
such as endometrial cancer. Looking again to data from the EPIC study,
people who followed a traditional Mediterranean diet most closely were
found to have significantly lower rates of cancer, and those who simply
consumed more olive oil and other unsaturated fats cut their cancer risk
by 9 percent.
Cancers of the digestive system are less
common when people eat larger quantities of fruits and vegetables, and
some of the nutrients contained in these foods are also linked to
protection against breast cancer. Olive oil may play a protective role
against breast, respiratory tract and colorectal cancers.
Similarly, diets high in grains and
fruits are associated with decreased incidence of osteoporosis, possibly
due to the effect of phytoestrogens (plant-derived estrogens) in
lentils, chick peas and other beans, the high levels of vitamins D, K,
folates and betacarotenes in fruits and vegetables, and the omega-3 oils
from certain fishes. Lower rates of rheumatoid arthritis have also been
linked with a diet high in fish, olive oil and cooked vegetables.
The Mediterranean Lifestyle—Food and
Culture
“The Mediterranean diet” is not actually
a diet in the sense most commonly used these days. It is not a weight
reduction program, but rather a general way of eating and food types
common to the countries that surround the Mediterranean Sea and thus
have certain climate and cultural traits in common. Many of these
countries share (or shared until recently) a heavy reliance on whole
grains, legumes, fruits and cooked vegetables, with the moderate
quantities of nuts, wine, fish, cheese and yogurt. Olive oil is the fat
of choice.
We’ve seen how these ingredients are
linked to various health benefits of a Mediterranean-type diet. Olive
oil has potent antioxidant properties that protect the heart by lowering
bad cholesterol, inflammation, and hypertension. Fruits and
vegetables—particularly tomatoes, with their lycopene—also likely owe
their benefits against cancer and heart disease to their antioxidant
effects.
Like olive oil, fish—particularly oily
fish like sardines and anchovies, both of which are popular in
Mediterranean cuisines—has been shown to benefit the heart and arteries
and may protect against Alzheimer’s disease through their omega-3
polyunsaturated fats.
Many of these same plant-based
antioxidants and nutrients are present in the red wine that is a feature
common to Mediterranean diets. French studies have found a link between
wine and reduced cardiovascular risk in people who consume high levels
of saturated fats. While some doubt has been cast on “the French
paradox,” there is evidence that a component of red wine called
resveratrol may reduce certain age-related effects and even inhibit
tumor growth.
Food is of course only one aspect of a
Mediterranean lifestyle. Climate and culture also contribute to the
health profile associated with the Mediterranean diet. The custom of the
moderate siesta may be linked to reduced deaths from heart attacks, and
the sunny climate and long daylight periods foster higher levels of
vitamin D and serotonin. In such an atmosphere, traditionally much more
of the business of life has occurred outdoors in a social and leisurely
manner. The Mediterranean diet in the largest sense involves not just
food but fresh rather than processed foods and a relatively active life.
Sadly, many aspects of the Mediterranean
lifestyle which contributed to the health benefits of their diet are now
in decline, as people live more stressful lives and adopt a diet higher
in meats, processed foods, and saturated fats. But perhaps some of these
losses will be offset as the world comes to understand the health
advantages of a Mediterranean diet.
People are living ever longer, and the
Mediterranean diet shows promise not only for extending their lives, but
for making those longer lives healthier and happier as well.
About the Author
Matthew Papaconstantionu, PhD was born
and raised in Patras, Greece. His favorite island is Crete. Having
learned its benefits first-hand, Matthew wants to make reliable
information about the Mediterranean diet more generally available.
Matthew enjoys researching the science behind traditional diets. In his
site, devoted to
best weight loss programs
reviews, Matthew blogs about
Medifast coupon 50
and
nutrisystem savings coupons,
two clinically researched diets.
References
1. Adherence to the Mediterranean
diet, long-term weight change, and incident overweight or obesity: the
Seguimiento Universidad de Navarra (SUN) cohort. Beunza JJ, and
colleagues. Am J Clin Nutr. 2010 Oct 20
2. Mediterranean dietary patterns and
prospective weight change in participants of the EPIC-PANACEA project.
Romaguera D, and colleagues. Am J Clin Nutr. 2010 Oct;92(4):912-21
3. Mediterranean diet and coronary
heart disease: is obesity a link? - A systematic review. Kastorini CM,
and colleagues. Nutr Metab Cardiovasc Dis. 2010 Sep;20(7):536-51
4. Mediterranean diet and red wine
protect against oxidative damage in young volunteers. Urquiaga I, and
colleagues. Atherosclerosis. 2010 Aug;211(2):694-9.
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